A Systematic Review of the Level of Evidence in Economic Evaluations of Medical Devices: The Example of Vertebroplasty and Kyphoplasty.

CONTEXT: Economic evaluations are far less frequently reported for medical devices than for drugs. In addition, little is known about the quality of existing economic evaluations, particularly for innovative devices, such as those used in vertebroplasty and kyphoplasty. OBJECTIVE: To assess the level of evidence provided by the available economic evaluations for vertebroplasty and kyphoplasty. DATA SOURCES: A systematic review of articles in English or French listed in the MEDLINE, PASCAL, COCHRANE and National Health Service Economic Evaluation databases, with limits on publication date (up to the date of the review, March 2014). STUDY SELECTION: We included only economic evaluations of vertebroplasty or kyphoplasty. Editorial and methodological articles were excluded. DATA EXTRACTION: Data were extracted from articles by two authors working independently and using two analysis grids to measure the quality of economic evaluations. DATA SYNTHESIS: Twenty-one studies met our inclusion criteria. All were published between 2008 and 2014. Eighteen (86%) were full economic evaluations. Cost-effectiveness analysis (CEA) was the most frequent type of economic evaluation, and was present in 11 (52%) studies. Only three CEAs complied fully with the British Medical Journal checklist. The quality of the data sources used in the 21 studies was high, but the CEAs conforming to methodological guidelines did not use high-quality data sources for all components of the analysis. CONCLUSIONS: This systematic review shows that the level of evidence in economic evaluations of vertebroplasty and kyphoplasty is low, despite the recent publication of a large number of studies. This finding highlights the challenges to be faced to improve the quality of economic evaluations of medical devices.

Economic Analysis of Kiva VCF Treatment System Compared to Balloon Kyphoplasty Using Randomized Kiva Safety and Effectiveness Trial (KAST) Data.

BACKGROUND: Vertebral compression fractures (VCFs) are the most common osteoporotic fractures and cause persistent pain, kyphotic deformity, weight loss, depression, reduced quality of life, and even death. Current surgical approaches for the treatment of VCF include vertebroplasty (VP) and balloon kyphoplasty (BK). The Kiva® VCF Treatment System (Kiva System) is a next-generation alternative surgical intervention in which a percutaneously introduced nitinol Osteo Coil guidewire is advanced through a deployment cannula and subsequently a PEEK Implant is implanted incrementally and fully coiled in the vertebral body. The Kiva System's effectiveness for the treatment of VCF has been evaluated in a large randomized controlled trial, the Kiva Safety and Effectiveness Trial (KAST). The Kiva System was non-inferior to BK with respect to pain reduction (70.8% vs. 71.8% in Visual Analogue Scale) and physical function restoration (38.1 % vs. 42.2% reduction in Oswestry Disability Index) while using less bone cement. The economic impact of the Kiva system has yet to be analyzed. OBJECTIVE: To analyze hospital resource use and costs of the Kiva System over 2 years for the treatment of VCF compared to BK. SETTING: A representative US hospital. STUDY DESIGN: Economic analysis of the KAST randomized trial, focusing on hospital resource use and costs. METHODS: The analysis was conducted from a hospital perspective and utilized clinical data from KAST as well as unit-cost data from the published literature. The cost of initial VCF surgery, reoperation cost, device market cost, and other medical costs were compared between the Kiva System and BK. The relative risk reduction rate in adjacent-level fracture with Kiva [31.6% (95% CI: -22.5%, 61.9%)] demonstrated in KAST was used in this analysis. RESULTS: With 304 vertebral augmentation procedures performed in a representative U.S. hospital over 2 years, the Kiva System will produce a direct medical cost savings of $1,118 per patient and $280,876 per hospital. This cost saving with the Kiva System was attributable to 19 reduced adjacent-level fractures with the Kiva System. LIMITATIONS: This study does not compare the Kiva System with VP or any other non-surgical procedures for the treatment of VCF. CONCLUSION: This first-ever economic analysis of the KAST data showed that the Kiva System for vertebral augmentation is hospital resource and cost saving over BK in a hospital setting over 2 years. These savings are attributable to reduced risk of developing adjacent-level fractures with the Kiva System compared to BK.

Vertebral body reconstruction: techniques and tools.

Vertebral augmentation techniques use image guidance for the percutaneous placement of spinal implants that stabilize a painful osteoporotic or pathologic vertebral compression fracture. The initial implant, acrylic bone cement, was injected through a bone needle into the vertebral body, a procedure referred to as vertebroplasty. A modification of this procedure, kyphoplasty, entails the temporary use of an inflatable balloon tamp before cement injection. Other techniques and the equipment required to perform these vertebral augmentation procedures have evolved significantly during the past two decades. It is now possible to perform vertebral body reconstruction in patients with painful fractures of compromised vertebrae with excellent outcomes in terms of sustainable pain relief and marked reduction in patient morbidity.

Assessment of different screw augmentation techniques and screw designs in osteoporotic spines.

This is an experimental study on human cadaver spines. The objective of this study is to compare the pullout forces between three screw augmentation methods and two different screw designs. Surgical interventions of patients with osteoporosis increase following the epidemiological development. Biomechanically the pedicle provides the strongest screw fixation in healthy bone, whereas in osteoporosis all areas of the vertebra are affected by the disease. This explains the high screw failure rates in those patients. Therefore PMMA augmentation of screws is often mandatory. This study involved investigation of the pullout forces of augmented transpedicular screws in five human lumbar spines (L1-L4). Each spine was treated with four different methods: non-augmented unperforated (solid) screw, perforated screw with vertebroplasty augmentation, solid screw with vertebroplasty augmentation and solid screw with balloon kyphoplasty augmentation. Screws were augmented with Polymethylmethacrylate (PMMA). The pullout forces were measured for each treatment with an Instron testing device. The bone mineral density was measured for each vertebra with Micro-CT. The statistical analysis was performed with a two-sided independent student t test. Forty screws (10 per group and level) were inserted. The vertebroplasty-augmented screws showed a significant higher pullout force (mean 918.5 N, P = 0.001) than control (mean 51 N), the balloon kyphoplasty group did not improve the pullout force significantly (mean 781 N, P > 0.05). However, leakage occurred in some cases treated with perforated screws. All spines showed osteoporosis on Micro-CT. Vertebroplasty-augmented screws, augmentation of perforated screws and balloon kyphoplasty augmented screws show higher pullout resistance than non-augmented screws. Significant higher pullout forces were only reached in the vertebroplasty augmented vertebra. The perforated screw design led to epidural leakage due to the position of the perforation in the screw. The position of the most proximal perforation is critical, depending on screw design and proper insertion depth. Nevertheless, using a properly designed perforated screw will facilitate augmentation and instrumentation in osteoporotic spines.